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From: Pedro Alves <palves@redhat.com>
To: Jan Kratochvil <jan.kratochvil@redhat.com>
Cc: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>,
	       gdb-patches@sourceware.org
Subject: Re: [PATCH] solib-svr4: Avoid unwanted shlib internal BPs When debugging Linux kernel or u-boot
Date: Fri, 01 Jun 2012 17:37:00 -0000	[thread overview]
Message-ID: <4FC8FDD2.7060407@redhat.com> (raw)
In-Reply-To: <20120601172214.GA21236@host2.jankratochvil.net>

On 06/01/2012 06:22 PM, Jan Kratochvil wrote:

> On Fri, 01 Jun 2012 18:21:28 +0200, Pedro Alves wrote:
>> --- a/gdb/solib-svr4.c
>> +++ b/gdb/solib-svr4.c
>> @@ -1707,7 +1707,7 @@ enable_break (struct svr4_info *info, int from_tty)
>>  	}
>>      }
>>
>> -  if (!current_inferior ()->attach_flag)
>> +  if (interp_name != NULL && !current_inferior ()->attach_flag)
>>      {
>>        for (bkpt_namep = bkpt_names; *bkpt_namep != NULL; bkpt_namep++)
>>  	{
> 
> It has a regression in the case below.
> 
> OTOH one has to strip _start to make it a regression as with _start GDB did not
> catch startup libraries even before.


Yeah, that's a really contrived example.  You're relying on stopping at main,
not when the DSO is really loaded (_dl_debug_state) to set the breakpoint.
I can see _start not existing, with the entry point named something else,
but if you strip your static binary to miss _dl_debug_state, you won't get
main either.  (and then static binaries that dlopen aren't something you'd
want to do normally.)

-- 
Pedro Alves


  reply	other threads:[~2012-06-01 17:37 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-01 15:01 [PATCH] solib-svr4: Avoid unwanted shlib internal BPs When debugging Linux kernel or u-boot with Abatron BDI emulator an error occurs: .. (gdb) tar remote bdi:2001 Remote debugging using bdi:2001 0xeff80050 in ?? () (gdb) mon reset (gdb) cont Continuing. Warning: Cannot insert breakpoint -1. Error accessing memory address 0xc0000000: Unknown error 4294967295 Joakim Tjernlund
2012-06-01 16:21 ` [PATCH] solib-svr4: Avoid unwanted shlib internal BPs When debugging Linux kernel or u-boot Pedro Alves
2012-06-01 18:05   ` Jan Kratochvil
2012-06-01 17:37     ` Pedro Alves [this message]
2012-06-01 18:05       ` Jan Kratochvil
2012-06-01 18:19         ` Pedro Alves
2012-06-01 19:08           ` Jan Kratochvil
2012-06-01 20:25         ` Mark Kettenis
2012-06-07  0:00       ` Maciej W. Rozycki
2012-06-08 12:10         ` Pedro Alves
2012-06-08 12:39           ` Jan Kratochvil
2012-06-08 13:07             ` Pedro Alves
2012-06-08 13:37               ` Mark Kettenis
2012-06-08 13:45                 ` Pedro Alves
2012-06-08 15:45           ` Maciej W. Rozycki
2012-06-01 18:07     ` Jan Kratochvil
2012-06-05 15:45   ` Pedro Alves

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